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A helix is a curved line formed by a point rotating around a center while the center moves up or down the z-axis. Helices are either right or left handed with curled fingers giving the direction of rotation and thumb giving the direction of advance along the z-axis. The threads of a screw are helical and therefore screws can be right- or left ...
The reason for the clockwise standard for most screws and bolts is that supination of the arm, which is used by a right-handed person to tighten a screw clockwise, is generally stronger than pronation used to loosen. Sometimes the opposite (left-handed, counterclockwise, reverse) sense of threading is used for a special reason.
In these dances the follower's right arm is normally used to lead a turn (most commonly by the leader's left arm, but sometimes by the leader's right arm when a cross-hand or "handshake" position is used), an inside turn is normally a left (counter-clockwise) turn, while an outside turn is a right (clockwise) turn.
The terms are derived from the Latin words for "left" (sinister) and "right" (dexter). Other disciplines use different terms (such as dextro-and laevo-rotary in chemistry, or clockwise and anticlockwise in physics) or simply use left and right (as in anatomy). Relative direction and chirality are distinct concepts.
Namely, they have positive values when they represent a rotation that appears clockwise when looking in the positive direction of the axis, and negative values when the rotation appears counter-clockwise. The opposite convention (left hand rule) is less frequently adopted. About the ranges (using interval notation):
This corresponds to a counterclockwise twist for the right forearm and a clockwise twist for the left (when viewed superiorly). In the forearm, this action is performed by pronator quadratus and pronator teres muscle .
When using this convention, left- or right-handedness is determined by pointing one's left or right thumb away from the source, in the same direction that the wave is propagating, and matching the curling of one's fingers to the direction of the temporal rotation of the field at a given point in space.
At the moment of throwing the bowling ball, the hand should be behind the ball and where the thumb (for a right-hander) is anywhere between 10-o'clock and 12-o'clock, and the two fingers are between 4-o'clock and 6-o'clock. Just before releasing the ball, the entire hand starts rotating in a counter-clockwise motion.